The invention relates to a method and apparatus for creating a flat planar laser beam.
Heretofore, it has been well known in the laser art to produce a cylindrically shaped laser beam which may be used for various physical functions. The formation of the laser beam is quite well known; however, it has been considered desirable to obtain a thin flat laser beam of a planar nature to accomplish certain functions not available with cylindrically shaped beams with a minimum of structural changes to existing laser structures. I am not aware of any present method or apparatus for creating a flat planar shaped laser beam. Therefore, the functions and desired results of a planar laser beam have not been obtained.
The use of lenses in laser beam structures is relatively new. The current use of lenses in laser beam structures is epitomized by the disclosure in U.S. Pat. No. 3,825,856, issued July 23, 1974 to Jacques Pezot in which an arrangement of lenses is used to select the Gaussian mode of operation of a laser beam. This patent utilizes lens configurations for altering the diameter of a laser beam thereby obtaining varying energy concentrations. Flat end mirrors are utilized for reflective purposes in some circumstances with convergent and divergent lenses to eliminate the high and low ends of the Gaussian curve of energy distribution to obtain a minimal dispersion through a small apertured diaphragm. This prior art reference does not speak in terms of obtaining planar laser beams and does not concern itself with the propagation of a flat planar laser beam.
In fact, the Pezot reference does not refer to focal point coincidence in any respect either for the purpose of beam concentration from large diameter to small diameter or for the creation of a flat planar laser beam in any respect.
More specifically Pezot speaks in terms of convergent lens system as a means of compensating for the optical selecting system. This teaching is diametrically opposed to the parallelism sought in the present invention.
Another prior art problem which the present invention obviates is that of beam dispersion over long distance transmission. In a recent development of the space program a regular cylindrical laser beam transmitted to the moon wound up with a four (4) mile dispersion pattern. If a flat planar laser light were transmitted at least in one plane the dispersion pattern would be minimal so that all the advantages that laser light concentration offers could be utilized.